Chapter 15 Cardiovascular System

1. Chapter 15Cardiovascular System

3. Heart Orientation Apex - directed anteriorly, inferiorly and to the left Base - directed posteriorly, superiorly and to the right Anterior surface - deep to the sternum and ribs Inferior surface - rests on the diaphragm Right border - faces right lung Left border (pulmonary border) - faces left lung

4. Heart Orientation Heart has 2 surfaces: anterior and inferior, and 2 borders: right and left

5. Surface Projection of the Heart Superior right point at the superior border of the 3rd right costal cartilage Superior left point at the inferior border of the 2nd left costal cartilage 3cm to the left of midline Inferior left point at the 5th intercostal space, 9 cm from the midline Inferior right point at superior border of the 6th right costal cartilage, 3 cm from the midline

6. Coverings of Heart

7. Wall of Heart

8. Chambers and Sulci of the Heart Four chambers 2 upper atria 2 lower ventricles Sulci - grooves on surface of heart containing coronary blood vessels and fat coronary sulcus encircles heart and marks the boundary between the atria and the ventricles anterior interventricular sulcus marks the boundary between the ventricles anteriorly posterior interventricular sulcus marks the boundary between the ventricles posteriorly

9. Chambers and Sulci

10. Chambers and Sulci

11. Right Atrium Receives blood from 3 sources superior vena cava, inferior vena cava and coronary sinus Interatrial septum partitions the atria Fossa ovalis is a remnant of the fetal foramen ovale Tricuspid valve Blood flows through into right ventricle has three cusps composed of dense CT covered by endocardium

12. Right Ventricle Forms most of anterior surface of heart Papillary muscles are cone shaped trabeculae carneae (raised bundles of cardiac muscle) Chordae tendineae: cords between valve cusps and papillary muscles Interventricular septum: partitions ventricles Pulmonary semilunar valve: blood flows into pulmonary trunk

13. Left Atrium Forms most of the base of the heart Receives blood from lungs - 4 pulmonary veins (2 right + 2 left) Bicuspid valve: blood passes through into left ventricle has two cusps to remember names of this valve, try the pneumonic LAMB Left Atrioventricular, Mitral, or Bicuspid valve

14. Left Ventricle Forms the apex of heart Chordae tendineae anchor bicuspid valve to papillary muscles (also has trabeculae carneae like right ventricle) Aortic semilunar valve: blood passes through valve into the ascending aorta just above valve are the openings to the coronary arteries

15. Myocardial Thickness and Function Thickness of myocardium varies according to the function of the chamber Atria are thin walled, deliver blood to adjacent ventricles

16. Thickness of Cardiac Walls

17. Heart Valves

18. Heart Valves

19. A-V valves open and allow blood to flow from atria into ventricles when ventricular pressure is lower than atrial pressure occurs when ventricles are relaxed, chordae tendineae are slack and papillary muscles are relaxed Atrioventricular Valves Open

20. A-V valves close preventing backflow of blood into atria occurs when ventricles contract, pushing valve cusps closed, chordae tendinae are pulled taut and papillary muscles contract to pull cords and prevent cusps from everting Atrioventricular Valves Close

21. Semilunar Valves SL valves open with ventricular contraction allow blood to flow into pulmonary trunk and aorta SL valves close with ventricular relaxation prevents blood from returning to ventricles, blood fills valve cusps, tightly closing the SL valves

22. Skeleton of Heart

23. Valve Function Review

24. Valve Function Review

25. Two closed circuits, the systemic and pulmonic Systemic circulation left side of heart pumps blood through body left ventricle pumps oxygenated blood into aorta aorta branches into many arteries that travel to organs arteries branch into many arterioles in tissue arterioles branch into thin-walled capillaries for exchange of gases and nutrients deoxygenated blood begins its return in venules venules merge into veins and return to right atrium Blood Circulation

26. Pulmonary circulation right side of heart pumps deoxygenated blood to lungs right ventricle pumps blood to pulmonary trunk pulmonary trunk branches into pulmonary arteries pulmonary arteries carry blood to lungs for exchange of gases oxygenated blood returns to heart in pulmonary veins Blood Circulation (cont.)

27. Blood Circulation Blood flow blue = deoxygenated red = oxygenated

28. Path of Blood Through the Heart

29. Path of BloodThrough the Heart

30. Coronary Circulation Coronary circulation is blood supply to the heart Heart as a very active muscle needs lots of O2 When the heart relaxes high pressure of blood in aorta pushes blood into coronary vessels Many anastomoses connections between arteries supplying blood to the same region, provide alternate routes if one artery becomes occluded

31. Coronary Arteries Branches off aorta above aortic semilunar valve Left coronary artery circumflex branch in coronary sulcus, supplies left atrium and left ventricle anterior interventricular art. supplies both ventricles Right coronary artery marginal branch in coronary sulcus, supplies right ventricle posterior interventricular art. supplies both ventricles

32. Coronary Veins Collects wastes from cardiac muscle Drains into a large sinus on posterior surface of heart called the coronary sinus Coronary sinus empties into right atrium

33. Blood Supply to Heart

34. Blood Supply to Heart

35. Angiogram of Coronary Arteries

36. Cardiac Cycle

37. Heart Actions

38. Heart Sounds

39. Heart Sounds

40. Cardiac Muscle Fibers

41. Conduction System of Heart Autorhythmic Cells Cells fire spontaneously, act as pacemaker and form conduction system for the heart SA node cluster of cells in wall of Rt. Atria begins heart activity that spreads to both atria excitation spreads to AV node AV node in atrial septum, transmits signal to bundle of His AV bundle of His the connection between atria and ventricles divides into bundle branches & purkinje fibers, large diameter fibers that conduct signals quicklyAutorhythmic Cells Cells fire spontaneously, act as pacemaker and form conduction system for the heart SA node cluster of cells in wall of Rt. Atria begins heart activity that spreads to both atria excitation spreads to AV node AV node in atrial septum, transmits signal to bundle of His AV bundle of His the connection between atria and ventricles divides into bundle branches & purkinje fibers, large diameter fibers that conduct signals quickly

42. Cardiac Conduction System

43. Cardiac Conduction System

44. Muscle Fibers in Ventricular Walls

45. Physiology of Contraction Depolarization, plateau, repolarization Depolarization Cardiac cell resting membrane potential is -90mv excitation spreads through gap junctions fast Na+ channels open for rapid depolarization Plateau phase 250 msec (only 1msec in neuron) slow Ca+2 channels open, let Ca +2 enter from outside cell and from storage in sarcoplasmic reticulum, while K+ channels close Ca +2 binds to troponin to allow for actin-myosin cross-bridge formation & tension development Repolarization Ca+2 channels close and K+ channels open & -90mv is restored as potassium leaves the cell Refractory period very long so heart can fill Depolarization Cardiac cell resting membrane potential is -90mv excitation spreads through gap junctions fast Na+ channels open for rapid depolarization Plateau phase 250 msec (only 1msec in neuron) slow Ca+2 channels open, let Ca +2 enter from outside cell and from storage in sarcoplasmic reticulum, while K+ channels close Ca +2 binds to troponin to allow for actin-myosin cross-bridge formation & tension development Repolarization Ca+2 channels close and K+ channels open & -90mv is restored as potassium leaves the cell Refractory period very long so heart can fill

46. Electrocardiogram---ECG or EKG EKG Action potentials of all active cells can be detected and recorded P wave atrial depolarization P to Q interval conduction time from atrial to ventricular excitation QRS complex ventricular depolarization T wave ventricular repolarization recording of electrical changes that occur in the myocardium used to assess heart�s ability to conduct impulses recording of electrical changes that occur in the myocardium used to assess heart�s ability to conduct impulses

47. Summary of Changes During Cardiac Cycle PHASES OF THE CARDIAC CYCLE Isovolumetric relaxation brief period when volume in ventricles does not change--as ventricles relax, pressure drops and AV valves open Ventricular filling rapid ventricular filling:as blood flows from full atria diastasis: as blood flows from atria in smaller volume atrial systole pushes final 20-25 ml blood into ventricle Ventricular systole ventricular systole isovolumetric contraction brief period, AV valves close before SL valves open ventricular ejection: as SL valves open and blood is ejectedPHASES OF THE CARDIAC CYCLE Isovolumetric relaxation brief period when volume in ventricles does not change--as ventricles relax, pressure drops and AV valves open Ventricular filling rapid ventricular filling:as blood flows from full atria diastasis: as blood flows from atria in smaller volume atrial systole pushes final 20-25 ml blood into ventricle Ventricular systole ventricular systole isovolumetric contraction brief period, AV valves close before SL valves open ventricular ejection: as SL valves open and blood is ejected

48. Regulation of Cardiac Cycle

49. Regulation of Cardiac Cycle

50. Blood Vessels

51. Arteries and Arterioles

52. Walls of Artery and Vein

53. Arteriole

54. Metarteriole

55. Capillaries

56. Capillary Network

57. Regulation of Capillary Blood Flow

58. Venules and Veins

59. Venous Valves

60. Blood Volumes in Vessels

61. Arterial Blood Pressure

62. Factors That InfluenceArterial Blood Pressure

63. Control of Blood Pressure

64. Control of Blood Pressure

65. Control of Blood Pressure

66. Venous Blood Flow

67. Central Venous Pressure

68. Pulmonary Circuit

69. Blood Flow Through Alveoli

70. Systemic Circuit

71. Major Vessels of Arterial System

72. Major Blood VesselsAssociated With Heart

73. Aorta and Its Principal Branches

74. Abdominal Aorta and Its Major Branches

75. Arteries to Neck, Head, and Brain

76. Cerebral Arterial Circle

77. Arteries to Shoulder and Upper Limb

78. Arteries to Thoracic Wall

79. Arteries to Pelvic Region

80. Main Branches of External Iliac Artery

81. Major Vessels of the Venous System

82. Major Veins of the Brain, Head, and Neck

83. Major Veins of the Upper Limb and Shoulder

84. Veins That Drain the Thoracic Wall

85. Veins That Drain the Abdominal Viscera

86. Hepatic Portal Vein

87. Main Veins of the Lower Limb and Pelvis

88. Life-Span Changes

89. Risk Factors for Heart Disease Risk factors in heart disease: high blood cholesterol level high blood pressure cigarette smoking obesity & lack of regular exercise. Other factors include: diabetes mellitus genetic predisposition male gender high blood levels of fibrinogen left ventricular hypertrophy

90. Clinical Application

91. By-pass Graft

92. Percutaneous Transluminal Coronary Angioplasty

93. Stent in an Artery Maintains patency of blood vessel

94. Periacarditis Cardiac Tamponade Rheumatic Fever Arrhythmias Congenital Heart Defects